GM Service Manual Online
For 1990-2009 cars only

Heater Hoses Replacement Inlet Hose - 5.0L, 5.7L, 7.4L

Removal Procedure

Tools Required

J 38723 Heater Line Quick Connector Separator

  1. Drain the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.

  2. Object Number: 257108  Size: SH
  3. Disconnect the inlet hose (1) from the generator bracket.
  4. Disconnect the inlet hose at the fender clip.
  5. Loosen the hose clamp at the heater core enough to slide the clamp away from the fitting on the inlet hose.
  6. Remove the hose clamp at the heater core, the water shut off valve, or the tee fitting.
  7. Disconnect the inlet hose from the heater core.

  8. Object Number: 220038  Size: SH
  9. Push the inlet hose (5) into the connector (1).
  10. Insert the J 38723 into the connector in order to release the locking tabs (2).
  11. Pull the retainer (4) and the inlet hose from the heater inlet connector.
  12. Inspect the O-ring sealing surface on the inlet hose.
  13. When replacing the heater inlet connector, remove the retainer from the hose.
  14. Discard the retainer.

  15. When replacing the inlet hose, but not the connector, complete the following steps:
  16. 12.1. Remove the retainer from the inlet hose.
    12.2. Reinsert the retainer in the connector.
  17. When reusing the inlet hose and the container, keep the retainer in place on the hose.

Installation Procedure


    Object Number: 220038  Size: SH
  1. Push the hose (5) into the connector (1) until the retainer tabs (3) lock.
  2. Pull back on the hose in order to verify for the proper engagement.

  3. Object Number: 257108  Size: SH
  4. Connect the inlet hose (1) to the heater core, the water shut off valve, or the tee fitting.
  5. Install the inlet hose clamp.
  6. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  7. Install the inlet hose mounting screw.
  8. Tighten
    Tighten the screw to 30 N·m (22 lb ft).

  9. Install the inlet hose to the fender clip.
  10. Add the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  11. Inspect the system for leaks.

Heater Hoses Replacement Outlet Hose - 5.0L, 5.7L

Removal Procedure

  1. Drain the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.

  2. Object Number: 257108  Size: SH
  3. Remove the outlet hose (2) from the fender clip.
  4. Remove the outlet hose clamp from the following components:
  5. • heater core
    • water shut off valve
    • tee fitting
  6. Disconnect the outlet hose from the heater core.
  7. Remove the outlet hose mounting screw.
  8. Remove the outlet hose from the generator bracket.
  9. Remove the outlet hose clamp from the water pump.
  10. Disconnect the outlet hose from the water pump.

Installation Procedure


    Object Number: 257108  Size: SH
  1. Connect the outlet hose (2) to the water pump.
  2. Install the outlet hose clamp to the water pump.
  3. Install the outlet hose to the generator bracket.
  4. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  5. Install the generator bracket mounting screw.
  6. Tighten
    Tighten the screw to 30 N·m (22 lb ft).

  7. Connect the outlet hose to the heater core.
  8. Install the outlet hose clamp to the heater core.
  9. Install the outlet hose to the fender clip.
  10. Add the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  11. Inspect the system for leaks.

Heater Hoses Replacement Outlet Hose - 7.4L

Removal Procedure

  1. Drain the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.

  2. Object Number: 257117  Size: SH
  3. Remove the outlet hose clamps.
  4. Remove the outlet hose (2) from the fender clip.
  5. Disconnect the outlet hose from the heater core.
  6. Disconnect the outlet hose from the radiator.

Installation Procedure


    Object Number: 257117  Size: SH
  1. Connect the outlet hose (2) to the radiator.
  2. Connect the outlet hose to the heater core.
  3. Install the outlet hose to the fender clip.
  4. Install the hose clamps.
  5. Add the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  6. Inspect the system for leaks.

Heater Hoses Replacement Inlet Hose - Diesel

Removal Procedure

Tools Required

J 38723 Heater Line Quick Connector Separator

  1. Drain the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.

  2. Object Number: 257112  Size: SH
  3. Remove the inlet hose (1) from the generator bracket.
  4. Remove the inlet hose mounting nuts.
  5. Loosen the inlet hose clamp at the heater core enough in order to slip the clamp away from the fitting on the inlet hose.
  6. Remove the inlet hose clamp at the heater core.
  7. Disconnect the inlet hose from the heater core.

  8. Object Number: 220038  Size: SH
  9. Push the inlet hose (5) into the connector (1).
  10. Insert J 38723 into the connector in order to release the locking tabs (2).
  11. Pull the retainer (4) and the inlet hose from the heater inlet connector.
  12. Inspect the O-ring sealing surface on the inlet hose.
  13. When replacing the heater inlet connector, remove the retainer from the hose.
  14. Discard the retainer.

  15. When replacing the inlet hose, but not the connector, complete the following steps:
  16. 12.1. Remove the retainer from the inlet hose.
    12.2. Reinsert the retainer in the connector.
  17. When reusing the inlet hose and the container, keep the retainer in place on the hose.

Installation Procedure


    Object Number: 220038  Size: SH
  1. Push the inlet hose (5) into the connector (1) until the retainer tabs (3) lock.
  2. Pull back on the inlet hose in order to verify for the proper engagement.

  3. Object Number: 257112  Size: SH
  4. Connect the inlet hose (1) to the heater core.
  5. Install the inlet hose clamp (7).
  6. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  7. Install the inlet hose screw.
  8. Tighten
    Tighten the screw to 30 N·m (22 lb ft).

  9. Add the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  10. Inspect the system for leaks.

Heater Hoses Replacement Outlet Hose - Diesel

Removal Procedure

  1. Drain the coolant. Refer to Cooling System Draining and Filling in Engine Cooling.

  2. Object Number: 257112  Size: SH
  3. Disconnect the outlet hose (2) from the radiator connection.
  4. Disconnect the outlet hose from the heater core connection.
  5. Remove the outlet hose from the outlet hose clip.
  6. Disconnect the outlet hose from the engine.
  7. Remove the hose clamps from the outlet hose.

Installation Procedure


    Object Number: 257112  Size: SH
  1. Install the hose clamps to the outlet hose (2).
  2. Connect the outlet hose to the engine.
  3. Connect the outlet hose to the radiator connection.
  4. Connect the outlet hose to the heater core connection.
  5. Install the outlet hose to the outlet hose clip.
  6. Add the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  7. Inspect the system for leaks.